Macroinvertebrates are animals without backbones of a size large enough to be seen by the unaided eye and which can be retained by a U.S. Standard No. 30 sieve (28 meshes per inch, 0. 595 mm openings).

---

Other /More definition:
Macroinvertebrates are animals without backbones that can be seen with the naked eye (caught with a 1 mm2 mesh net). Includes insects, crayfish, snails, mussels, clams, fairy shrimp, etc.